The present invention relates to a cap which is to be attached to a tip portion of a writing implement, application implement or the like.
In general, a cap which is to be attached to a writing implement or the like is comparatively small in size. Accordingly, there is a likelihood that an infant mistakenly swallows the cap which in turn chokes the throat. If the throat should be completely blocked by the cap, the infant will probably be suffocated before a doctor arrives on the scene. Accordingly, it is extremely preferable that the cap has a structure in which a passage for respiration can be secured even if the infant swallows the cap by mistake.
As disclosed in Japanese Unexamined Patent Publication No. 1-157898, there has been provided a cap having an air passage formed in an outer periphery of the cap for rendering a tip side space of the cap communicate with a tail side space of the cap to secure a respiration passage.
With the above-mentioned cap, it is necessary to provide the air passage in the outer periphery of the cap. Consequently, the structure of the cap is complicated. In addition, there is a disadvantage that the diameter of the cap is unnecessarily large. In particular, in a case where a clip is attached to the cap with an annular body of the clip mounted on the outer periphery of the cap, the cap has a larger diameter, which consequently mars the appearance.